title: Conserved microRNA miR-8 blocks activation of the Toll pathway by upregulating Serpin 27 transcripts.
abstract: microRNAs (miRNAs) play significant regulatory roles in gene expression at the post-transcriptional level. This includes modulating processes such as development, immunity, cancer, and host-pathogen interactions. It was recently shown that the phylogenetically deeply conserved miRNA, miR-8, plays a role in maintaining the homeostasis of immunity by suppressing the production of anti-microbial peptides. In this study, we show that miR-8 from the insect Plutella xylostella positively regulates the transcript levels of the serine protease inhibitor Serpin 27, which has been shown to regulate activation of the Toll pathway and prophenoloxidase involved in the melanization response in insects. Interestingly, miR-8 is downregulated following parasitization by Diadegma semiclausum leading to significant declines in Serpin 27 transcript levels. This allows upregulation of antimicrobial peptides, such as gloverin, that are controlled by the Toll pathway and activation of proteolytic cascades essential for humoral immune responses to foreign invasion.
authors.affiliation: School of Biological Sciences; The University of Queensland; St Lucia, QLD Australia.
authors.forename: Kayvan
authors.initials: K
authors.lastname: Etebari
authors.forename: Sassan
authors.initials: S
authors.lastname: Asgari
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004156:Catechol Oxidase / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D006790:Host-Parasite Interactions; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D007814:Larva / Q000235:genetics / Q000469:parasitology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics* / Q000276:immunology / Q000469:parasitology*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D015843:Serpins / Q000235:genetics* / Q000378:metabolism; D051193:Toll-Like Receptors / Q000378:metabolism*; D015854:Up-Regulation; D014863:Wasps / Q000235:genetics / Q000502:physiology
chemical_list: D004792:Enzyme Precursors; D019476:Insect Proteins; D036341:Intercellular Signaling Peptides and Proteins; D035683:MicroRNAs; D011506:Proteins; D015843:Serpins; D051193:Toll-Like Receptors; C107617:gloverin; C038451:pro-phenoloxidase; D004156:Catechol Oxidase
keywords: Serpin 27; gloverin; insect immunity; miR-8; microRNA